State Road 6563 (NM 6563), also known as the Sunspot Scenic Byway,[2] is a 15.530-mile-long (24.993 km) two-lane state highway in Otero County, New Mexico, United States.
NM 6563 is one of only three four-digit state highways in New Mexico (the others being NM 1113 and NM 5001).[1] It takes its number from the wavelength of the Hydrogen-alpha spectral line (6563 Å) used by scientists at the observatory to study the solar chromosphere and to locate solar flares on the Sun.[4]
The solar observatory added signs along the highway in 2011 with the names of the planets as part of a 1:250 million model of the distances between planets in the Solar System.[5]